Magneto-strictive oscillator



April 124, 1942..

U. JOHN MAGNETO- STRICTIVE OSCILLATOR Filed March 18, 1959 arf/:rae M463 GBE/4 721 SMAMLEQ 5245770/ 7*? SMLLEB ATTORNEYS.

Patented pr. 14, 1942 Es PATENT ori-lcs MAGNETO-STRICTIVE OSCLLATOR Ulrich John, Kiel, Germany, assignor to Electroacustic Gesellschaft mit beschrnkter Haftung, Kiel, Germany, a corporation of Germany Application In March 1s, 1939, serial No. 262,691 Germany March 28, 1938 7 Claims. (Cl. 177-386) Thepresent invention relates to magnetostrictive oscillators, and in particular to such oscillators which are excited by longitudinal oscillations produced in the core structure. Some- 'times such oscillations are designated as being oi the mushroom type. If such an oscillator is attached in a housing or to any base on which it is to serve,` the difculty arises that by such attachments its tuning is changed. Up to the present, attempts were made to remove thesedefects by' cushioning the magneto-strictive oslcillator in its supports, for instance by interposing sound damping material such as rubber, cork, or the like. Aside from the factthat such expedients can never entirely remove the de- 'fects above-mentioned, they involve on the other hand technical disadvantages.. In particular are such cushioned attachments-undesirable for submarine sound oscillators, because the oscillator,

-due to the effect of the great outside pressure produced by the water, can easily shift in itsl cushionedfseat'and becomes subject to disturbing mechanical influences.

These disadvantages are overcome 'according to the present invention by shaping the magnetostrictive oscillator so that it can be rigidly mounted in its support without thereby affecting vits tuning. According to the present invention, the two masses-of a magneto-strictive oscillator which are coupled'by a magneto-strictivc elastic element in the usual manner are besides coupled masses of the magneto-strictive oscillator for the purpose of the present invention.

Figure 2 is of explanatory nature and shows a circuit diagram (substitute scheme) representing an electrical equivalent of the mathematical relation between the masses andthe elastic elements in Figure l, and

Figure 6 is aperspective view of the embodiment shown in Figure 1 and illustrates how the laminae of the entire oscillating system are arranged.

Referring to Figure 1, I and 2 are the two masses of a magneto-strictive oscillator of the mushroom type, which masses are coupled by an elastic element 4. This element consists, in weilknown manner, ofl magneto-strictive material. surrounded by an energizing winding; According to the invention, elastic suspension elements 5 and 5" are laterally attached respectively to masses I and 2, and these elastic elements in turnV are connected together by masses 3 and 8'. These suspension elements 5, 5' and the masses 3,

, 3' represent in their combination an elastic system containing dead-weight masses and by which through further elastic elements with elastically 'unbiased masses, i. e. dead weight masses, which together with the magneto-strictive oscillator form an oscillatory system. The proportioning of the elements of this system are such that the nodal zones which is formed during the oscillation of the system become located in said unbiased masses. In these zones which do not partake in the oscillatory motion of the magnetostrictive oscillator, the oscillating system'may,

the mainV masses I and Zlof Vthe oscillator proper are connected in addition to their connection by the magneto-strictive member 4. Further, according to the invention, the elastic suspension elements 5 and 5', that is to say, their .elasticity is dimensioned so that the masses 3, 3"become nodal points of the entire oscillatory system during its oscillation. Since these masses 3. '3' remain stationary, the oscillatory system may be connected at these masses to the support I2, I2, as shown in Figure 1, without thereby impairlng the natural frequency of the oscillationof masses I, 2. In the specific case in whichthe massesl and 2 are equal, the elasticity of auxiliary elastic elements 5 and 5 must also be equal. If masses I and 2 are different from each other, the elas- Aticity of the auxiliary elastic elements 5 and 5' according to the present invention, beY safelyv Y rigidly connected with its support, such as a housing or the hull plate of a ship or the like, without impairing the tuning of the magnetostrictive oscillator proper.

In the accompanying drawing, a few modifications of an arrangement according to the invention are shown as examples. ingwhich auxiliary masses maybe connected to the Figures 1, 3, 4 and 5 represent, more or less diagrammatically, several structural forms in must be inversely proportionalvto the masses of the main system to which the elements are connected. This way of calculating and dimension-V ing the elastic elements will be understood 'from the electrical substitute schem'e of Figure 2.

Referring to Figure 2, if we assume' the masses I and 2 of Figure 1 to -be representedby the electric inductances I and 2 in Figure 2, and -if these In the drawinductances are arranged in a Wheatstone bridge circuit, then the elasticity I of Figure 1 is represented by the capacitor 4 in Figure 2, and theY elastic .elements 5, 5' of Figure 1 are respectively represented in Figure 2 by capacitors 5 and E. In order to balance the bridge in Figure 2, the rela-` tions between the constants of the bridge must be such that in the bridge inductance 3, which is the equivalent of the masses 3, 3' cf Figure 1, no current llows. Correspondingly, if the mechanical masses in Figure 1 which correspond with the electrical masses of Figure 2 are properly rel.. atively dimensioned such as the electrical masses and values are dimensioned in Figure 2 to produce a bridge balance in that igure,l a stationary condition of masses 3, 3' will be produced in Figure 1; in other words, the nodal point of the system will reside in these masses. The electrical substitute scheme ofFig. 2 serves to facilitate determining the relation of the magnitudes of the masses and elasticities relatively to one another, but is not intended to be necessarily an equivalent in other respects such as the spatial arrangement or location of the energy source.

. sides in the manufacture of the oscillator.

tors of Figs. 3 and 4. The elastic element 8l in Fig. 6 has an outer surface flush with the outer surfaces of the masses I and 6 so that a continuous sound-translating surface is obtained.

A particular feature of the invention also re- In order to satisfy the requirement that the auxiliary system 5, 3, 3 should be connected with masses I and 2 without an elastic bias, the entire oscillating system is made as a whole in the form of apackage of laminae, preferably of nickel, each of the laminae containing all elements of the oscillating system.

Figure 6, shows the same oscillating system as shown in Figure 1 without the support I2, I2 perspectively and shows how the laminae are arranged. `Each` of the laminae .lying in the sight has the'form as shown in Figure 1. In the In Figure 3 a modification is shown in which the auxiliary elastic suspension elements 5 which are attached to mass i, are connected to that mass so that they are flush with its outer surface. Such a form is of advantage in case the outer surface of mass I is shaped as a sound radiating surface. In an arrangement such as is shown in Fig-ure 3, it becomes easily possible v gto make the radiating surface of the oscillator,

iflush with the housing. Such a flush arrangef-vment is, however, not limited to a pla'ne surface of the sound radiator and the casing. As shown fin Figure 4, the 'entire system may be shaped so that the surface ofthe sound radiating and the auxiliary elastic suspension elements 5, 5 which connect it with the masses 3, 3', constitute together a curved or streamline-shaped body. In this case, the auxiliary elastic suspension elements '5'. 5- gradually merge into masses 3,3'.

. auch a form is particularly suited for oscillators which are mounted on a support which protrudes through the bottom of a vessel and which is exposedjto the flow of the water.-

case ol Figure 4, each oi the laminae has the form as shown in Figure 4 and is arranged in a package, of which the cross-section has a streamline-shape and of which the longitudinalsection has a rectangular shape.

I claim:

1. A magneto-strictive oscillator having a sound-translating surface, in particular for submarine signalling, comprising a main oscillatory system having two main masses and magnetostrictive elastic. means interconnecting said main masses, only one of said main masses forming part of said sound-translating surface to be effective in the `acoustic signalling operation while According to a modiication shown-in Figure 5,

la' plurality of magneto-strictive systems may be joinedinto a single oscillator in which the masses I and 2 of the first system are connected by corresponding auxiliary elastic elements 8 and 9 with the masses 6 and I of thesecond system. Il; this case the dimensions of the constants of the constituent elements of the systems must be made so that of each two adjacent systems one -taken in its entirety, becomes located within the nodal zone of the other system (or, generally speaking, of its neighboring system), whereby the other or neighboring system assumes the place ofthe masses 3, 3f in Figure 1 in the calculation i of the constants. f Such an arrangement may be particularly suitable for a group arrangement In which the systems are placed a half wave-length M2 apart. The above requirements are fulfilled, for instance, if the interconnected systems are and 8 are proportionally smaller than the elasticities of 5' and 9. In the oscillator shown in- Fig. 6, only on mass I or 6 of each oscillatory system forms part of the sound-transmitting surface, while the other mass 2 or fldoes not participate in the sound reception or transmission but forms substantially a counterpoise for mass l or 6. In this respect, this embodiment resembles the oscilla,-A

. said other main mass is arranged separate from said surface to-form substantially a counterpoise for said rst main mass, electric circuit means having a coilmagnetically coupled with said main oscillatory system to transmit oscillatory energy between said circuit means and said sys tem, andv at least one auxiliary system interconnecting said two main masses separately from said elastic `meansrand arranged separate from said coilso as vto be substantially ineffective as regards saidv energy transmission, said auxiliary system having. two elastic members connected with said two main masses respectively and having elasticities inversely proportional to the magnitudes of said two masses, and an auxiliary unelastic .mass interconnecting said elastic membersand formi Ig` a nodal pointand supporting element-of the oscillator` 2:.-Y A magneto-strictive oscillator having a sound-translating surface, in particular for submarine signalling, comprising a main oscillatory system vl'1avi,ng,-ft'wo main masses and magnetost'rictive elastic".A eans interconnecting said main massea' only one" of said main masses'forxning partei said `soul1 j-translating surface to be effective in the, ao stic signalling operation while slaidother mainjfm'ass is arranged separate from said surface tdfjform substantially a counterpoise'for said first main mass, electric circuit means havingia 'coil magnetically coupled with saidmain oscillatory system to transmit oscillatory energy between said circuit means and said system, and at least one auxiliary system interconnecting said two-,nain masses separately from said elastic means and arranged separate from saidv coil so as to be substantially ineffective as regards-said energy transmission, said auxiliary system having two elastic members connected with vsaid two main masses respectivelyand having'. elasticities inversely proportional to the magnitudes of said two masses, and an auxiliary unela'stic mass interconnecting said elastic members and forming a nodal point and supporting eletainng portion of said two main masses, said elastic means, said two elastic members and said auxiliary mass.

3. A magneto-strictive oscillator, in particular for submarine signalling, comprising a main oscillatory system having two main masses and magneto-strictive elastic means interconnecting said main masses, electric circuit means having a coil magnetically coupled with saidmain oscillatory system to transmit oscillatory energy between said circuit means and said system, and at least. one auxiliary system interconnecting said two main masses separately from said elastic means and arranged separate from said coil so as to be substantially,Vineective as regards said energy transmission, said auxiliary systeml having two elastic members connected with said two main masses respectively and having elasticities inversely proportional to the magnitudes ofsaid two masses, and an auxiliary unelastic mass interconnecting said elastic members and forming a nodal point and supporting element of the oscillator, one of said two main masses together with said two elastic members of said auxiliary system forming a continuous outer surface to be effective as the sound-translating surfaceof the oscillator, while said other'main mass is arranged separate from said surface to form substantially a counterpoise for said iirst main mass.

4. A magneto-strictive oscillator having a sound-translating surface, in particular for submarine signalling, comprising a main oscillatory system having two main masses of Vdifferent magnitudes and magneto-strictive elastic means'interconnecting said main masses, only one of said main masses forming part of said sound-translating surface to be effective in the acoustic signalli'ng operation, said other main mass being arranged separate from said surface so as to form substantially a counterpoise for said first mass, electric circuit means having a coil magnetically coupled with said main oscillatory system to transmit oscillatory energybetween said circuit means and said system. and at least one auxiliary system interconnecting said two ,main masses separately from said elastic means and arranged separate from said coil so as to be substantially ineffective as regards said energy transmission, said auxiliary system having two elastic members for submarine signalling, comprising a main oscillatory systemhaving two main masses and ,magnetstrictive elastic means interconnecting said main masses, electric circuit means having a coil magnetically coupled with said main oscillatory system to transmit oscillatory energy between said circuit means and said system, and at least one auxiliary system interconnecting said two main masses separately from said elastic means and arranged separate from said coil so as to be substantially ineffective as regards said energy transmission, said auxiliary system havling two elastic members connected with said two main masses respectively and having elasticities inversely proportional to the magnitudes of said two masses, and anauxiliary unelastic mass in- Y terconnecting said elastic members and forming a nodal Vpoint and supporting-elementV of the oscillator, one of said two main masses together with said two elastic members and at least part of said auxiliary mass forming a continuous curved outer surface of the oscillator whose center portion formed by said latter main mass serves as substantially the sound-translating surface, while said other main mass is arrangedseparate from said surface to form substantially a counterpoise for said first main mass.

6. In a magneto-strictive oscillator, in particular for submarine signalling, having a plurality of oscillating systems, each system being composed of two masses and a magneto-strictively elastic element interconnecting said two masses. and auxiliary elastic elements each coupling one of said masses individually with one mass of the neighboring system so that each oscillating system in its entirety forms a nodal point for the oscillations of its neighboring system.

7. A magneto-strictive oscillator having a sound-translating surface, in particular for submarine signalling, having a plurality of oscillating systems, each system being composed of two masses and a magneto-strictively elastic element interconnecting said two masses, and auxiliary elastic elements each coupling one of said masses individually with one massof' the neighboring system so that each of said systems forms substantially a nodal point for the oscillations of its neighboring system, only one of said two masses of each system having an outer surface forming connected with said two main masses respectively y part of said sound-translating surface while the other mass of each system is arranged separate from said latter surface to form substantially a counterpoise for the first mass, each auxiliary elastic element interconnecting said nrst masses having an outer surface ush with said outer surfaces of said rst masses so -as to form a continuous sound-translating surface.Y

ULRICH JOHN. 

